Fluid pump for watercraft



Jan. 9, 1968 s. KUETHER 3,362,371

FLUID PUMP FOR WATERCRAFT Filed March 21/ 1966 9 Sheets-Sheet 1 Jan. 9, 1968 s. KUETHER 3,362,371

7 I FLUID PUMP FOR WATERCRAFT Filed March 21. 1966 v 9 Sheets-Sheet 2 Jan. 9, 1968 s. KUETHER 3,362,371

FLUID PUMP FOR WATERCRAFT Filed March 21, 1966 Q 9 Sheets-Sheet 5 Jan. '9, 1968 FLUID PUMP- FOR WATERCRAFT I Filed March 21, 1966 FIG.4

III I M I02 I 86 I \s s. KUETHER 3,362,371

' 9 SheetsSheet 4 Filed March 21, 1966- Jan. 9, 1968 v s, KUETHER v 3,362,371

FLUID PUMP FOR WATERCRAFT 9 Sheets-Sheet 5 Jan. 9, 1968 s. KUETHER 3,362,371

FLUID PUMP FOR WATERCRAFT 9 Sheets-Sheet 6 Filed March 21, 1966 Jan. 9, 1968 srKUETHER ,3 7

v FLUID PUMP FOR WATERCRAFT Filed March 21. 1966 r 9 Sheets-Sheet 7 Jan. 9, 1968 s. KUETHER 3,362,371

, FLUID PUMP FOR WATERCRAFT Filed March '21, 1966 9 Sheets-Sheet 8 an- ,1968 SKUETHEQ 3,362,371

FLUID PUMP FOR WATERCRAFT Filed March 21, 1966 9 Sheets-Sheet United States Patent FLUID PUMP FOR WATERCRAFT Siegfried Kuether, La Salie, Ontario, Canada, assignor to Tamco Limited, Ontario, Canada Filed Mar. 21, 1966, Ser. No. 536,133 Claims priority, application Canada, Oct. 22, 1965, 943,563/65 9 Claims. (Cl. 114-151) ABSTRACT OF THE DISCLOSURE A fluid pump or bow thruster for watercraft that consists of a cylindrical housing oriented vertically in the hull of the craft. The pump has a plurality of intake conduits leading into the upper end of the housing and the exhaust comprises a nozzle that is slidable in the housing to a retracted position within the craft and an extended position in which the nozzle is projected below the keel of the craft. Two coaxial shafts in the housing serve to (a) rotate the nozzle 360 with respect to the craft and (b) rotate the impeller means to provide thrust from the nozzle.

This invention relates to fluid pumps for use in watercraft or, more specifically, to the type of pumps presently known as bow thrusters which are located in or near the bow section of ships for holding the latter motionless in a current. This is effected by generating thrust with the pump and directing its discharge or exhaust downstream into the current.

In one type of known application, bow thrusters have been installed in vessels used in oceanographic survey work to make more accurate the sounding and ocean floor contour readings. The open ocean currents in which these crafts must operate often reach a speed of three knots per hour. This known type of bow thruster consists of open propellers positioned near the bow that could be lowered below the keel line of a ship, from a well in the hull, and retracted when not in use. This prior arrangement suffered from inherent disadvantages such as the vulnerability to damage of the open propellers; structural weaknesses inherent in the angular drive mechanisms for the propellers; and the excessive leverage when extended below the keel line.

A specific example of the prior art in this field is exemplified in bow thrusters of the Pehrsson-Mende type. This design utilizes a tunnel or conduit extending from the port to the starboard side of a craft and transverse to the keel line or longitudinal axis of the craft. A venturi-like shaft is concentrically positioned in the tunnel and it rotatably supports a centrally positioned screw. Bow thrusters of this transverse type are useful as a steering aid in narrow river channel navigation and as an aid in docking or casting off movements.

Transverse thrusters do, however, include several inherent disadvantages. Firstly, and of least importance, all the applied thrust is directed only normal to the longitudinal axis of the ship. This renders a transverse thruster as inflexible and too limited in operation for open water orientation. It must be acknowledged, however, that transverse thrusters are quite adequate for limited use but known types suffer from a second disadvantage in impeller or screw design. In presently used transverse thrusters, the direction of thrust is changed by changing the pitch of the blades on the impeller. Although the pump pressure is changed, say, from port to starboard, the screw blades are of aerodynamic configuration which develop problems in cavitation in their hydrodynamic role and are therefore highly inefiicient.

One aspect of the present invention provides solutions and improvements over the known transverse thrusters by providing a similar type of fluid pump in which a proper hydrodynamic screw can be utilized to provide a highly eflicient compact pump unit.

Other aspects of the present invention overcome many disadvantages of the prior art by providing fluid pumping units at, above, or below the keel line of a water craft and which can be revolved 360 so that thrust can be directed to any desired angle to port or starboard, forward or aft from the craft. In one embodiment, the present invention provides a fully extensible and retractable thrust nozzle which, when retracted, is still capable of giving thrust normal to the centre line of the craft for aiding docking and casting ofI maneuvers.

According to a further aspect of the invention, a fluid pump for watercraft comprises a cylindrical housing adapted for mounting in the bow section of said watercraft; at least one fluid inlet conduit interconnecting said housing with the exterior of said craft whereby said housing is in communication with ambient waters adjacent said craft; a thrust impeller coaxially positioned in said housing for rotation therein; drive means connected to said impeller for rotating the latter; a thrust nozzle adapted to receive fluid under pressure from said impeller and to exhaust the latter angularly from said craft to create directional thrust, said nozzle cooperating with said housing and being concentrically positioned with respect thereto; and means operatively connected to said nozzle for rotating the latter 360 with respect to said housing and watercraft.

The invention is illustrated, by way of example, in the accompanying drawings in which:

FIGURE 1 is a perspective view, partly sectioned, showing one embodiment of the present invention installed in a watercraft.

FIGURE 2 is a sectional view taken through the bow thruster of FIGURE 1 looking forward towards the bow of the craft;

FIGURE 3 is a sectional view taken along line 3-3 of FIGURE 2 and locking to the starboard side of the craft;

FIGURE 4 is a plan view of part of the steering mechanism taken along lines 4-4 of FIGURE 3;

FIGURE 5 is a cross-sectional view taken through the bow section of a craft, looking forward, and showing a second embodiment of the present invention;

FIGURE 6 is a cross-section taken along lines 66 of FIGURE 5;

FIGURE 7 is an enlarged fragmentary view of nozzle steering means shown in FIGURE 6;

FIGURE 8 is a plan view of a third embodiment of a bow thruster of the present invention;

FIGURE 9 is a cross-sectional view taken along lines 9-9 of FIGURE 8;

FIGURE 10 is a transverse sectional view taken through the keel showing an end view of the thruster;

FIGURE 11 is a view in cross-section of a further embodiment of the present invention showing a bow thruster of the transverse type; and

FIGURES 12a and 1212 show the types of screw blades used in transverse thrusters of the prior art and the present invention respectively.

Referring to FIGURE 1 of the drawings, a bow thruster indicated generally at 1 includes a vertically disposed impeller housing 2 that extends upwardly from the keel 4 of a watercraft 6. The hull 8 of the craft 6 is provided, below the water line, with a plurality of intake conduits 10 extending from the sides of the hull 8 radially inwardly to communicate with the impeller housing 2. Spaced upwardly from the keel 4 there is provided a passageway or tunnel 12 that is transverse to the keel 4 or longitudinal axis of the craft 6.

As shown in FIGURES 2 and 3, the housing 2 includes an upper tube 14 and lower tube 16, the upper end of which is integral with or detachably receives the inner terminal ends of the conduits 10. The connected or telescoped area of the tubes 14 and 16 provide an annular shoulder 18 on which is seated the peripheral flange 26 of a flow-directing venturi 22 concentrically positioned within the lower tube of housing 2. Disposed also coaxially in the housing 2, specifically in the lower tube 16 and below the venturi 22, is a rotatable screw or impeller 24; a cage of flow straightening vanes 26; and a thrust nozzle 28.

The venturi 22, as well as the cage 26, is secured against rotation in the tube 16 and a hollow drive shaft 31) passes freely through the centre of the venturi 22 and is fixed to a central hub section 32 of the impeller 24. The lower end of drive shaft 30 is terminated in the cage 26 and sup ported therein by a seal 34 together with horizontal and vertical thrust bearings 36 and 38 respectively. Similar bearings 40 and 42 hold the shaft 30 for rotation in the upper end of the venturi 22 and these bearings are retained in place by an end cover 44.

The top end of the upper housing tube 14 is provided with a cover plate 46 through which the upper end of the shaft 30 passes where it is provided with a driven sheave 48. The latter is connected by a plurality of belts 50 to a driving sheave 52 on variable speed drive means, in the present example an electric motor 54 mounted in the hull 8 of the craft.

Coaxially mounted within the drive shaft 30 is a steering shaft 56 that is secured at its lower end to the top of the thrust nozzle 28. The upper end of the shaft 56 is connected to a hydraulic or pneumatic cylinder 58 by known means such as a pin 60 and collar 62. A nozzle rotating or steering assembly, indicated generally at 64, is mounted atop the upper housing tube 14 and is operatively connected to the shaft 56 for rotating the latter and the thrust nozzle 28. The steering assembly 64 may be of a diversity of designs although in the example shown (FIG- URE 4), the mechanism comprises a pair of splined collars 66 through which the shaft 56 is slidable and which is operated by a pair of pneumatic or hydraulic cylinders 68.

The thrust nozzle 28 includes a plurality of passageways 70, the cross sectional areas of which are gradually constricted from the upper or intake end 72 of the nozzle to the exhaust end 74 thereof. The exhaust end 74 is angulated approximately 90 with respect to the upper end and the nozzle housing 2. As shown in FIGURES 2 and 3, nozzle 28 is enclosed in a casing 76 having its lower end formed with the configuration of the keel 4 or hull 8 of the craft. During open water travel, the nozzle 28 (in retracted position) is disposed to a forward or aft direction as shown in FIGURE 3.

The nozzle 28 together with its casing 76 is extensible and retractable in the lower housing tube 16. In the retracted position, the nozzle may be rotated to an aligned position with the transverse lower passage 12 for docking or casting olf maneuvres where thrust is required only normal to the longitudinal axis of the craft. For open water rotation of the nozzle, the cylinder 58 is actuated to lower the shaft 56 downwardly through the drive shaft 30 whereby the nozzle 28 and its casing 76 are dropped a predetermined extent below the keel 4 as shown in phantom line in FIGURE 3. In this position the nozzle 28 may be rotated to any desired angle in a full 360 cycle in relation to the lower housing tube 16.

When the impeller 24 is rotated by the motor 54 and drive shaft 30, water is drawn in through the conduits to the venturi 22 which changes the direction of the water downwardly and also reduces turbulence thereof whereby the flow reaches the impeller 24 as a relatively undisturbed mass of water from which may be derived maximum thrust. Rotation of the impeller 24 causes a given degree of lateral swirl or turbulence, the amount of which is in relation to the rotational speed of the impeller. This swirling action of the flow is wasted motion and the cage of straightener vanes 26 removes the swirl to convert the motion into a head building force as the flow enters the upper end of the nozzle 28. The need for the vanes 26 is normally dictated by the speed, diameter and pitch of the impeller 24 so that in some units where lateral flow diversion is so slight as to be negligible, the vanes may be omitted from the thruster unit.

As the flow enters the nozzle 24 at the upper end thereof, the gradual contraction in cross section of the nozzle effects a building up of the head of the flow. From the vane cage 26 below the impeller 24 to the exhaust end of the nozzle 28, the omnilateral pressure caused by the head of the flow in combination with the nozzle passage construction is converted into thrust as the pressured waters emerge through the nozzle exhaust 74.

It will be appreciated from FIGURES 2 and 3 that accessibility to the bow thruster unit is readily alforded for routine maintenance or replacement of parts. There is no need for dry-docking the vessel or the engagement of divers if such work must be carried out. With removal of the elements secured to the upper ends of the shafts 3t) and 56, the steering shaft 30 may be pulled upwardly from the housing 2 to bring with it the connected nozzle 28; vanes 26, impeller 24 and venturi 22. By such removal the ambient water will, of course, enter and rise in the tubes 14 and 16. However, due to the fact that the top end of the tube 14 is above the water line (FIGURE 3) the water will not overflow and enter the interior of the craft. The elements of the thruster may therefore be laid out and exposed for ease of inspection or the like.

A second embodiment of the invention is shown in FIGURES 5, 6, and 7. In this particular form, a rotatable thrust nozzle is again utilized although it is not retractable. However, its lowest point is spaced slightly above the keel line of the craft. As shown in FIGURE 5, the bow thruster comprises a cylindrical housing 80 having a central hub 82 and fixed flow straightener vanes 84 extending radially from the hub to the wall of the housing 80. An impeller 86 is disposed within the housing 80 over the vanes 84 and is also provided with a hub 88. A drive shaft 90 is secured coaxially at its lower end to the impeller hub 88 and at its upper end to. a variable speed motor 92.

Inlet conduits 94 extend from the sides of the hull 96 inwardly and downwardly to the housing 80 to communicate with and substantially encircle the impeller 86. It will be noted that conduits 94 gradually constrict in cross sectional area as they approach the housing 80 to provide a head building force to the incoming flow. In order to limit vertical movement of the shaft 90 and to prevent end to end engagement of the impeller 86 and vanes 84, a bearing block 98 is incorporated between the conduits 94. As shown in FIGURE 5, block 98 encloses a pair of thrust bearings 100 supporting a collar 102 on the drive shaft 90.

The lower end of the housing 80 is conically shaped as at 81 and terminates in a peripheral mounting flange 104 by means of which the housing is supported by a shoulder 106 in the lower region of the hull.

A thrust nozzle 108 is positioned for 360 rotation in the conical portion 81 of the housing 80 and is retained therein by means of an arrangement of pins 110 and rollers 112 which serve the dual purpose of holding the nozzle 108 in position while at the same time acting as a bearing. As shown in FIGURE 7, the pin 110 is recessed at the roller end and limits the axial play or movement of the roller 112 through a set screw adjustment 114. It is also to be noted that every other pin (110a) is offset approximately .20" in the housing 80. Reference to FIGURES 6 and 7 shows that the conical portion 81 of the housing includes an annular channel 118 to accommodate a ring gear 120 fixed to the nozzle 108 by pins 122.

The ring gear 120 is in mesh with and rotated by a worm gear 124 mounted in the flared portion 81 and the proper mesh is maintained by a plurality of guide bolts 126 in a peripheral channel 128 of the ring gear 120. The worm gear 124 may be rotated by known types of drive means, not shown.

Water flow enters the intake conduits 94, which may be provided with louvers 128, and builds up a head force as it reaches the impeller 86. The lateral swirl imparted to the flow by the impeller may be removed by provided vanes 84 and the flow is exhausted from the thrust nozzle 108 which, like the first described embodiment of FIG- URE 2, is rotatable 360. It is to be noted that the lowest point of the nozzle 108 is above the keel line of the craft.

FIGURES 8, 9 and illustrate a further embodiment of the present invention wherein the drive motor and impeller drive shaft are placed horizontally, i.e., substantially parallel to the longitudinal axis or keel line of the craft.

As shown in FIGURE 9, a housing 130 encloses an impeller 132 that is rotated by and secured to a drive shaft 134, the free or outer end thereof being detachably connected to a variable speed motor 136, by a coupling 138. A plurality of flow straightener vanes 140 are fixed in the housing 130 adjacent the impeller 132, the vanes extending from the wall of the housing radially inwardly to a central hub 142. The intake end 144 of the housing 130, as shown in FIGURE 8, receives the inner ends of a pair of water conducting conduits 146.

As in the previously described embodiment, the conduits 146 communicate with ambient waters outside the hull of the craft and they are progressively constricted in area throughout their length as they approach the housing 130.

The exhaust end of the housing 130 is formed in an elbow 148 and rotatably mounted to the lower end thereof is a thrust nozzle 150. The latter is rotated by a steering shaft 152 that has its lower end secured to a central guide 154 in the nozzle 140, the upper shank of the shaft being rotatably mounted in an adjacent central guide 156 and bearing block 158 in the elbow 148 of the housing 130.

Water enters the thruster through the conduits 146 (with may utilize louvers 160, FIGURE 10) and is drawn into the impeller 132 where thrust is applied. The vanes 140 remove any swirl in the flow before it is exhausted from the elbow 148 into the nozzle 150 which, as in the previous embodiments, is fully orientable. The steering shaft may be rotated by means such as that shown in the embodiment of FIGURE 2.

A further embodiment of the invention is shown in FIGURE 11 which illustrates a .bow thruster of the transverse type. A conduit 162 is mounted transversely in the hull of a ship (not shown) and a drum-like housing 164 is placed within the conduit. A screw or thrust impeller 166 is mounted for rotation in the drum housing 164 by a nacelle 168 having a plurality of supporting struts 170, the latter acting also as straightening vanes for the water passing through the conduit.

The impeller 166 is secured to a horizontally disposed drive shaft 172 which is rotated by motor means (not shown) via bevel gears 174 and a pinion shaft 176, disposed within the nacelle. Shaft 176 is rotated in turn by a parallel motor shaft 178 through suitable gears 180482.

Mention has been made earlier in the disclosure of the disadvantages of known lateral thrusters regarding the use of reversible pitch propellers, one type being shown in FIG. 12a. Obviously, to be able to provide thrust in two directions, the propeller shown in FIG. 12a must be of substantially the same chord profile on each of its surfaces. However, the use of this aerodynamic type of propeller creates cavitation problems when used in a lateral pump, with the result that there is a high degree of ineflicienoy present. For example, to provide approximately 24,000 lbs. of thrust, a lateral pump using an aerodynamic, reverse-pitch propeller needs a conduit opening of approximately eight feet in diameter. Tests indicate that the pump illustrated in FIG. 11 using a propeller blade design similar to FIG. 12b provides the same thrust with a three foot diameter conduit.

In order then to provide thrust to starboard or port with an impeller that is not reversible in pitch, the present embodiment provides means for rotation of impeller 166 and its nacelle 168 within the drum housing 164. The lower end of the nacelle 168 is provided with an orientation shaft 184 that projects downwardly from the drum 164 and shaft 184 is sealed from drum 164 by a packing gland 186 at its lower end and suitable packing 188 seals the upper end of the nacelle in the drum. Suitable drive mechanism (not shown) rotates the shaft 184 through a worm shaft 192 and a cooperating gear 194 secured to the lower end of the shaft.

It will be appreciated that, as a result of rotation of the nacelle 168, the pinion shaft 176 and its associated gear 182 would rotate about the motor shaft 178 and its gear 180 so as to lie in the position R indicated in peeked line.

Moreover, it is within the realm of the present invention to provide a bow thruster similar to that of FIGURE 11 with the exception that two contra-rotating or twin impellers would be used in which one impeller can be geared higher than the other to increase thrust through the tube.

I claim:

1. A fluid pump for watercraft comprising:

(a) a cylindrical housing having adapted for mounting in the bow section of a watercraft, said housing being vertical in disposition and including an upper tube and a lower tube secured together in axial alignment;

(b) a-plurality of fluid inlet conduits interconnecting said housing with the exterior of said craft whereby said housing is in communication with ambient waters adjacent said craft;

(c) a thrust impeller coaxially positioned in the lower tube of said housing for rotation therein;

(d) a venturi mounted in said housing above said impeller adapted to direct thereto flow entering said housing through said inlet conduits;

(e) a thrust nozzle rotatably mounted in said lower tube adapted to receive fluid flow under pressure from the impeller and to exhaust the flow angularly from said craft to create directional thrust;

(f) drive means connected to said impeller for rotating the latter in said lower tube; and

g) steering means operatively connected to said nozzle for rotating the latter 360 with respect to said lower tube and watercraft.

2. A fluid pump according to claim 1 including a tunnel communicating with the lower tube of said housing transverse to and adjacent the keel line of said watercraft, said tunnel being open to said ambient waters and being adapted to receive fluid flow from said nozzle.

3. A fluid pump according to claim 1 including radially disposed, flow straightening vanes in said lower tube intermediate said impeller and said nozzle.

4. A fluid pump according to claim 1 wherein said nozzle is vertically extensible and retractable out of and into said housing.

5. A fluid pump for watercraft comprising:

(a) a cylindrical housing adapted for mounting in the bow section of a watercraft, said housing being vertical in disposition and including an upper tube and a lower tube secured together in axial alignment;

(b) a plurality of fluid inlet conduits interconnecting said housing with the exterior of said craft whereby said housing is in communication with ambient waters adjacent said craft;

(c) a thrust impeller coaxially positioned in the lower tube of said housing for rotation therein;

(d) a venturi mounted in said housing above said impeller adapted to direct thereto flow entering said housing through said inlet conduits;

(e) a thrust nozzle rotatably mounted in said lower tube adapted toreceive fluid flow under pressure from said impeller and to exhaust the flow angularly from said craft to create directional thrust;

(f) drive means for rotating said impeller comprising a driven shaft concentrically and rotatably mounted in said venturi, the lower end of said driven shaft being secured at its lower end to said impeller and the upper end extending upwardly through said upper tube and terminating beyond said housing; a sheave secured to the upper end of said driven shaft and motor means connected to said sheave for rotating the latter and said driven shaft;

(g) steering means operatively connected to said nozzle for rotating the latter 360 with respect to said lower tube and watercraft; and

(h) a tunnel extending transversely from the lower tube adjacent the keel line of said craft adapted to provide an exhaust outlet from said nozzle normal to the keel of said craft.

6. A fluid pump according to claim wherein said steering means comprises a shaft slidably mounted within said driven shaft and secured at its lower end to said nozzle, the upper end of said shaft extending above said housing, means connected to said shaft adjacent its upper end for rotating said shaft and said nozzle; and a ram connected to the upper terminal end of said shaft adapted, when actuated, to extend said nozzle, in said lower tube,

downwardly below the keel line of a watercraft whereby said nozzle may be rotated'to provide directional thrust at any angle normal to said housing.

7. A fluid pump according to claim 6 wherein said nozzle is enclosed in a casing slidable and rotatable in said housing, the configuration of the lower end of said casing conforming to that of said keel when said nozzle and casing are in a retracted position.

8. A fluid pump according to claim 5 wherein the diameter of said lower tube is less than the diameter of the adjacent upper tube, said housing including a cover on its upper end above the water line of said craft which, when removed, permits upward removal from said housing of the venturi, impeller, and nozzle.

9. A fluid pump according to claim 5 wherein said nozzle includes a plurality of flow passages, the cross sectional area thereof constricting. gradually toward the exhaust end of said nozzle.

References Cited UNITED STATES PATENTS 2,214,656 9/1940 Briggs l15-16 2,699,138 1/1955 Dyer 114-151 2,702,516 v 2/1955 Tinker 11516 3,098,464- 7/1963 Holland 11512 ANDREW H. FARRELL, Primary Examiner. 

